Sink



FIG. 1 is a front perspective view of a sink in accordance with thepresent design;

FIG. 2 is a front elevational view thereof,

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a left side elevational thereof; and,

FIG. 6 is a top plan view thereof.

The broken lines shown are included for the purpose of illustrating aportion of the sink that form no part of the claimed design.

CLAIM The ornamental design for a sink, as shown and described.